Which of Following Would Be Considered an Example of a Valid

Which of following would be considered an example of a valid contract?

A) Nancy agrees to buy her 15-year-old neighbor's car for $10,000.
B) George offers to pay Libber $1,000 for killing his neighbor's wife and Libber agrees to it.
C) Tim owes Peter money, but the statute of limitations has run out.
D) Tam owes Peters money, but before the statute of limitations ends, Tom is declared bankrupt.
E) Tom owes Pete money, but Pete has waited too long to collect it and the statute of limitations has run out; however, Tom promises to repay half the amount.